This application claims the priority benefit of Japanese Patent Application No. 2000-355838, filed on Nov. 22, 2000, and entitled xe2x80x9cA Base Plate Structure, A Transfer System, And Method And Apparatus For Assembling A Head Gimbal Assembly.xe2x80x9d
1. Technical Field
The present invention relates to an apparatus and method of assembling a head gimbal assembly (to be referred to as an HG assembly) for a hard disk drive. More specifically, the invention relates to an apparatus and method of assembling an HG assembly by using members in a series state.
2. Description of the Related Art
Referring to FIGS. 25 through 29, the construction of a HG assembly is shown. FIG. 25 is a perspective view showing the appearance of an HG assembly 51 (a suspension section 59 to be described later) before a slider is attached thereto, and FIG. 26 is an exploded view showing the configuration. The HG assembly 51 comprises a stacked layer structure of a base plate 52, a load beam 53, and a flexure 54. A flat surface 53a of the load beam 53 is joined to an opposed flat surface 52a of the base plate 52 by a method to be described later.
In this case, positioning is accomplished such that an opening 53c of the load beam 53 is superimposed on an opening 52c of the base plate 52, a reference opening 53b of the load beam 53 is superimposed on a reference opening 52b of the base plate 52, and an edge 52d of the base plate 52 is aligned with an indicator line 201 along the longer sides of an oblong opening 53d formed in the load beam 53. The load beam 53 is made of an elastic stainless steel having a thickness of approximately 0.038 to 0.05 mm, so that it is made thin, light, and can be kept sufficiently stiff.
Flanges 53e for strengthening the load beam are formed at the edges of a tapered portion 53m excluding an area near the oblong opening 53d. The tapered portion 53m extends longitudinally from the joined portion between the load beam 53 and the base plate 52. The portion where the oblong opening 53d is formed corresponds to a hinge portion 53f. The hinge portion maintains resilience even after it has been bent, as will be described later.
A tapered oval-shaped guide opening 53g and a generally rectangular opening 53h are formed in the tapered portion 53m. A gimbal pivot 53i to be described later, that lifts upwards, is formed in the protruding portion that extends from the center of the hinge portion 53f side of the opening 53h to the center of the opening 53h, and a tab 53j is formed at the leading end of the tapered portion 53m through the medium of a warped support 53k. 
The flexure 54 is made of a stainless steel with desired elasticity and a thickness of approximately 20 micrometers, for example, and part of the flexure is fixedly joined to the load beam 53. At this point, the reference opening 54b of the flexure 54 is superimposed on the reference opening 53b of the load beam 53, and the guide opening 54c of the flexure 54 is superimposed on the guide opening 53g of the load beam 53. The portion of the flexure 54 leading from an indicator line 202 is not joined so as to be movable.
An extendable joint 54d is formed in the flexure 54. The joint is disposed in a position to be superimposed on the hinge portion 53f of the load beam 53 so as not to prevent the elastic action of the hinge portion 53f when the flexure is joined to the load beam 53. An arch-shaped opening 54e is formed in the unjoined portion of the flexure 54, and a flexure tongue 54f protruding toward the center of the opening 54e is formed in the center of the bottom close to the leading end of the flexure 54.
An integral-type conducting lead 55 having four leads is also disposed on the flexure 54. In the integral-type conducting lead 55, four leads 55a to 55d (refer to FIG. 26) are provided so as not to touch to each other through a very thin insulating sheet 55e. One end of each of the leads is disposed on a connector portion 54a of the flexure 54. These lead ends are aligned so as to form a multi-connector 55f. The other ends of the leads are formed such that they can be respectively connected to the pads for four bonding pads 56a to 56d (shown in FIG. 29) formed in the slider 56.
The hinge portion 53f of the load beam 53 of the HG assembly 51 excluding the slider 56, configured as described above, is bent by approximately 19 degrees, for example, as shown in the dot-dash line in FIG. 25. This bending occurs due to plastic deformation, so that this bending angle is naturally maintained. Herein, the parts that exclude the slider 56 from the HG assembly 51, shown in FIG. 25, will be referred to as a suspension section 59.
In the slider 56, a magneto resistive read head to be referred to as an MR head 57 for reading data and an electromagnetic induction-type write head 58 are disposed in predetermined positions. Incidentally, the heads in FIG. 26 are just illustrated for reference, so that their positions in the drawing are not accurate ones. Each of the heads has two leads not shown, and leads are connected to the four bonding pads 56a to 56d shown in FIG. 29, respectively. The slider 56 is attached to the flexure tongue 54f of the flexure in FIG. 27 to be described later, with an adhesive.
Next, the arrangement of a pair of flexure arms 54g and 54h formed on both sides of the opening 54e of the flexure 54, a pair of openings 54i and 54j formed in the vicinity of the leading end of the flexure 54, the gimbal pivot 53i formed in the load beam 53, and the slider 56 attached to the flexure tongue 54f will be described.
FIG. 27 is a partially expanded view of the leading end of the HG assembly 51 before the slider 56 is attached, or the suspension section 59. FIG. 28 is a vertical sectional view of the portion indicated by an indicator line 203 in FIG. 27, as seen in the direction of arrow H. FIG. 29 is a perspective view of the leading end of the HG assembly 51 with the slider 56 attached to the flexure tongue 54f. 
As described before, the gimbal pivot 53i (shown in FIG. 28) is formed in the load beam 53. The flexure arms 54g and 54h of the flexure 54, which extend without being joined elastically support the flexure tongue 54f coupled thereto. The flexure tongue 54f is brought into contact with and supported by the gimbal pivot 53i due to joining of the flexure 54 to the load beam 53. The contact point is on an axis 200X in FIG. 27, corresponding to the center line of the flexure 54 in the longitudinal direction. An axis 200Y that passes through the contact point and is perpendicular to the axis 200X is also shown in FIG. 27. At this time of the contact, the flexure arms 54g and 54h are bent to some extent to press the flexure tongue 54f against the gimbal pivot 53i. 
The slider 56 is attached to the flexure tongue 54f such that its center is generally superimposed over the point where the flexure tongue 54f keeps in contact with the gimbal pivot 53i, as indicated by the broken line in FIG. 28. The slider 56 can be thereby rotated to some extent with respect to the axes 200X and 200Y, and can be tilted to a predetermined degree in all directions.
The four leads 55a to 55d (in FIG. 27) are fixed to the flexure 54 up to a leading end 55g of the insulating sheet 55e. The four leads are also fixed to a platform 53n in the leading end of the flexure 54 through the insulating sheet 55e, on the opposite side of the flexuretongue 54f with the two openings 54i and 54j interposed therebetween.
From the leading end 55g of the insulating sheet 55e to the platform 53n, the four leads 55a to 55d are bent along the flexure arms 54g and 54h in pairs to shape like cranks, being suspended in air without being brought into contact to each other. The other ends of the paired leads 55a to 55d are bent to extend from the platform 53n to the flexure tongue 54 through the two openings 54i and 54j, and then comprise the lead pads 55h to 55k for the bonding pads 56a to 56d (in FIG. 29), respectively. The bonding pads are formed in the slider 56 to be attached to the flexure tongue 54f. 
As shown in FIG. 28, although part of the lead pad 55i is supported by the platform 53n for the strengthening purpose, the lead pad 55i, for the most part, is suspended in air. Further, it is preferable to form the lead pad 55i to have approximately the same thermal capacity as the bonding pad 56b. Other lead pads are formed in the same manner.
Further, as shown in FIG. 27, a pair of crank-shaped limiters 54m and 54n that extend downwards are formed on both sides of the flexure tongue 54f of the flexure 54. When the flexure 54 is joined to the load beam 53, the limiters 54m and 54n are disposed with their leading ends extended downwards through the opening 53h of the load beam 53, as shown in FIG. 28. With this arrangement, if the unjoined portion of the flexure 54 is displaced to be further separated from the load beam 53 by some action, the leading ends of the limiters 54m and 54n are brought into contact with an underside 53q of the load beam 53, thereby serving to prevent the flexure and the load beam from being separated more than necessary.
When the HG assembly 51 configured as described above is assembled, trays or blocks are conventionally prepared as assembling jigs, and the base plate 52, load beam 53, and flexure 54 are positioned by using these assembling jigs to be stacked and then joined to one after another.
In order to complete the manufacturing process of the suspension section 59, the hinge portion 53f of the suspension section 59 of the HG assembly 51 is bent in the direction of arrow F (in FIG. 25) by approximately 19 degrees, for example, before the slider 56 is attached. When the slider 56 is attached to the flexure tongue 54f of the suspension section 59 and then the bonding pads of the slider are electrically connected to the lead pads of leads, trays or blocks are also used as the assembling jigs for positioning or fixing each of the members.
3. Problems to be Solved by the Invention
As described above, when uncompleted HG assemblies are transferred for each of the manufacturing processes, the assembly should always be mounted on the assembly jig such as a tray or a block for transference. For this reason, it becomes necessary to prepare the assembling jigs that are at least numerically equal to the uncompleted HG assemblies remaining at the respective manufacturing processes. Thus, the space efficiency of workspace is reduced, and the workplace is put in disorder. In addition, manufacturing cost rises with the number of the assembling jigs required, and management of these assembling jigs is time-consuming and inconvenient.
The process of attaching the slider and the process of connecting the slider to the leads are performed with the hinge portion of the HG assembly already bent. Accordingly, after these processes are finished, the bending state of the hinge portion might be changed and might not be kept in the desired state.
It is accordingly an object of the present invention to provide a more efficient method of assembling an HG assembly that eliminates the need for assembling jigs such as trays or blocks during its manufacturing processes. Another object of the invention is to provide a method of assembling an HG assembly, which reduces variations in the bending state of the hinge portion, thereby enhancing yield.
Various embodiments of an apparatus and method for assembling a hard disk drive HG assembly are disclosed. When uncompleted HG assemblies are transferred for each of the manufacturing processes, the uncompleted HG assembly should always be mounted on the assembly jig such as a tray or a block for transference. For this reason, assembling jigs, the number of which is at least equal to the number of the uncompleted HG assemblies remaining at the respective assembly processes would be needed. Accordingly, the efficiency of work space is reduced, and a rise in manufacturing cost is brought about by the need for the assembling jigs.
A base plate and a load beam that comprise stacked-layer members for an HG assembly are respectively formed in a series manner. A load beam series 4 is stacked on a base plate series 3 and transferred by a transfer system 2 in the form of the stacked-layer series to undergo the necessary assembly processes such as layer joining, slider attachment, and electrical connections between the terminals thereon.